Effect of snow crystal fin arrangements on thermal transfer and energy storage/release characteristics in a concentric tube latent heat energy storage unit

The layout and number of fins critically impact the melting/solidification performances of latent thermal energy storage (TES) systems. Given this, and inspired by snow crystals (SCs) in nature, this study proposes a novel twin-branched SC fin. The effect of structural layouts of SC fins on the energy storage/release performances of a concentric tube TES system equipped with triple and quadruple SC fins has been numerically investigated, adopting the enthalpy-porous medium method. The results reveal that natural convection has an important effect on the melting process and its intensity can be altered by changing the fin arrangement, while thermal conduction governs the solidification process. Compared to traditional rectangular fins, the maximum reduction of 82.8% in melting time is achieved by the triple SC fins, which yields a decrease of 21.1% in melting time compared with the quadruple SC fins. However, the quadruple SC fins offer a better solidification performance, which can respectively reduce solidification time by 66.4% and 48.2% when compared to the rectangular fins and the triple SC fins.